All this discussion of the merits of an AOA presentation in the AF447 accident is interesting and doubtless instructive, but the fact is surely that once the aircraft got to 40+ deg AOA, there was precious little chance of any stall recovery. Theoretically a sustained pitch down... to -30 deg or so... would have been effective, but who on earth would ever have done that in a large civil transport at night, AOA presentation or no AOA presentation? The authorities would be far better employed thinking how to ensure that crews have the required skills to keep the aircraft straight and level in all circumstances where controls are effective, than running down the UPRT road. The crew spectacularly failed on that flight and any suggestion that a crew with that skill set could cope successfully with UPRT is ridiculous IMHO.
Yes there are additional measures that could conceivably be taken to further improve the stall warning system on the A330, but as an old boss of mine once said in a slightly different context 'this [wind tunnel] is fool-proof, but it's not bloody fool proof'. Most improvements come at the expense of further complexity, which brings its own problems.